Seafloor massive sulfide deposits contain bonanza grades of gold, silver, copper and zinc metals. The deposits are often found at depths of one kilometre or more. They are characterised by active chimneys or smokers venting fluids at over 300C, with extremely low pH values. Mining of these deposits presents risks for both industry and governments at orders of magnitude higher than terrestrial mining This paper briefly discusses some of the core risks concerning the development of SMS mining including: technical, economic, environmental, legal, social, and research and development._x000D_
Until and unless these risks are eliminated or minimised, the embryonic deep sea mining industry will remain just that, and these deposits will remain a fascinating, unexploited geological curiosity.